Statin drugs are inhibitors of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase. This class of drugs block the metabolic pathway of intracellular mevalonic acid and reduce the intracellular cholesterol synthesis by competitively inhibiting the rate-limiting enzyme for endogenous cholesterol synthesis, HMG-CoA reductase, so as to increase the number and the activity of the low density lipoprotein (LDL) receptor on the surface of the feedback-stimulated cell membrane (mainly of hepatic cells), increase the clearance rate of serum cholesterol, and reduce the level thereof. Statin drugs can also inhibit the liver from synthesizing apolipoprotein B-100, so as to reduce the synthesis and secretion of triglyceride-riched AV and lipoprotein. In addition, early-stage application of statin drugs in patients suffered from acute coronary syndrome can inhibit the inflammatory response of the vascular endothelium, stabilize atherosclerotic plaque, improve the functions of the vascular endothelium; delay the degree of atherosclerosis (AS), and have anti-inflammatory, neuro-protective and anti-thrombosis effects. Accordingly, they have a very broad prospect of application.
The syntheses of currently marketed statin drugs, such as atorvastatin, pitavastatin, simvastatin, and rosuvastatin, all require using the chiral glycol side chain of formula A as a starting material.

In patent application WO 03006656A, 2,4-dideoxy hexose or 2,4,6-trideoxy hexose is used as an important intermediate, which undergoes oxidation, acetalation and hydrolysis to give the alcoholic side chain intermediate.

Patent application WO 0206266A reports a route for synthesizing a series of tert-butyl (4R-cis)-6-chloro-2,2-dimethyl-1,3-dioxane-4-acetate compounds from 6-chloromethyl-4-hydroxy tetrahydro-2H-pyran-2-one, wherein Y represents Na, Ca or a tetraalkylammonium.

Patent applications US 2006004200A and WO 2008059519A report a synthetic process in which tert-butyl (4R-Cis)-6-hydroxymethyl-2,2-dimethyl-1,3-dioxane-4-acetate is oxidized to an aldehyde side chain intermediate.

In the above routes, there are some problems in the aspects of synthesis of the starting materials, selection of the route, and separation and purification of the intermediates, which lead to high cost for synthesis and low overall yields. Therefore, developing a synthetic process with low-cost, environment friendliness and high product quality would have very high economic value and social value.